Quick-return lifting-jack



(No Model.) 2 Sh3etsSheet 1. J. A. MEAD 81; U. JOHNSON. QUICK RETURNLISTING JACK.

I i i.

ATTORNEY Patented Mar. 14, 1893.

(No Model.) I 2 Sheets-Sheet 2,

J. A. MEAD & 0; JOHNSON.

QUICK RETURN LIFTING JACK.

PatentedMar. 14, 1893.

.ILE...

lNVENTOHS flow ATTORNEY.

FNOTO-LITHQ. WASHINGTON 0. a

'UNITED STATES PATENT OFFICE.

JOHN A. MEAD AND CHARLES JOHNSON, OF RUTLAND, VERMONT.

QUICK-RETURN LlFTlNG-JACK.

SPECIFICATION forming part of Letters Patent No. 493,336, dated March14, 1893. Application filed November 3, 1892. Serial No. 450,827- (Nomodel.)

To all whom it may concern.-

Be it known that we, JOHN A. MEAD and CHARLES J oHNsoN, citizens of theUnited States, residing at Rutland, in the county of Rutland and Stateof Vermont, have invented certain new and, useful Improvements inQuick-Return Lifting-Jacks; and we do hereby declare the following to bea full, clear, and exact description of the invention, such as willenable others skilled in the art to which it appertains to make and usethe same.

Our invention relates'to an improved jackscrew, and it consists in theconstruction and arrangement of the parts of the same, which will bemore fully hereinafter described, and pointed out in the claims.

The object of our invention is to provide a quick return jack which issimple and effective in its construction and operation, strong anddurable, easily handled, quickly operated, and readily understood,positive in its results, and cheaply manufactured. We attain this objectby the construction of a jack screw, as illustrated in the accompanyingdrawings, wherein likeletters of reference indicate similar parts in theseveral views, and in which Figure 1 is a vertical perspective view ofthe jack complete and ready for use. Fig. 2 is a sectional sideelevation, showing the jack with the parts all in position. Fig. 3 is arear view showing the jack with the outer shell re- -moved, and showinggears, worm, and sectional view of housing. Fig. 4 is a view of the wormshaft and a suitably arranged housing with removable caps on each sideto hold oil or greased waste. Fig. 5 is a perspective View of thelifting bar. Fig. 6 shows in perspective a circular block of metalhaving toothed projections on its periphery, the radial lines thereofleading direct from the circumference toward the center, and the teethand spaces being of the same width. Fig. 7 is a perspective view of thepinion or worm wheel which is operated by the worm, with teeth shown ofsuch construction as to prevent the pinion from turning upon the worm,when in use, independently of the operator. Fig. 8 is a horizontalsectional view of the lever for operating the jack, showing all theparts in position. Fig. 9 is a view in pervwithin the outer shell D.

spective of the pinion which works in the rack on the lifting bar. thepawl and sliding block. Fig. 11 is a view of a plate or cover to protectthe ratchet wheel and block in the jack operating lever. Fig. 12 is aperspective View of a dog to be pivoted in the shell to support thegearing and to hold the worm in mesh with the worm wheel, and Fig. 13 isa View of a cap, formed to fit on the upper extremity of the lifting barand upon which the load may rest.

A represents the frame of the jack, having a broad base A braced andstrengthened by ribs a, and a rectangular shaped passage through thewhole length and an opening a in front about one half the length of thejack which connects with the above passage and receives a lifting bar Bof rectangular form keeping it in a central position. This lifting bar Bhas a rectangular shaped foot S projecting from the lower end of the barand integral with or fixedly secured thereto for use in lifting a loadnear the ground. The bar has toothed projections B or a rack on oneside.

O is a vessel shaped housing, having suitable bearings with removablecaps 0 0 see Fig. 4. In the hearings in this housing is mounted theshaft of the worm E, see Figs. 3 and4, of suitable form. This shaft hasa rectangular shaped end M on which ratchet wheel F and operating leverF are suitably mounted. Underneath the shaft in its housing is providedsufficient space for greased waste and oil. The vessel shaped housing 0has, at its inner end, a projection C with an aperture N by means ofwhich and a shaft the housing is 'pivotally secured at this end Outershell D on one side has a vertical slot D cut therein through whichprojects the squared end M of the worm shaft. Housing C is held in ahorizontal position within the outer housing, as shown,.by means ofadog'J suitably pivoted at W in an aperture in the lower part of the'outer shell D and provided with a weighted lower end J to hold the dognormally in a vertical position. When in this position the upper end Jof the dog contacts with the bottom of housing 0, and holds the housingin the position stated. When thelower weighted Fig. 10 is a View of Vtoo end J of this dog is swung outwardly, the end of the vessel shapedhousing, not pivoted, will of its weight fall downward.

D represents a worm wheelhaving teeth on its outer circumference to fitinto and to work with the spiral shaped grooves of the worm E. Thiswheel fits on a squared shaft I on shaft 1' of the pinion G, see Fig. 9.This shaft is suitably mounted in the upper part of the outer shell insuch a manner that pinion G is in mesh withrack B on the lifting bar,and wheel D is in gear with the worm E when the vessel housing C is heldin a horizontal position by the dog J. Pinion G may be made integralwith its shaft 1' and the teeth of the pinion are of suificient width topermit rack B to be easily engaged thereby. On shaft 1 at the ends oftheteeth may be formed flanges H H to strengthen the teeth of the pinion.

F is a cylindrical block of metal with a central rectangular shapedaperture, and a ratchet wheel F formed on one end. The aperture in thisblock tits the squared endM of the worm shaft.

F represents a lever for operatingthe jack. This lever has one end ofelliptical forrn hollowed out to fit over the end ofshaft M, and theratchet wheel mounted thereon, see Fig. 1. The other end F has anaperture therein for the insertion of a handle not shown.

Within the larger end of this lever is pivoted a double pawl O ofcrescent shape, provided with an operating handle T which projectsthrough an aperture in thelever. This pawl in the rear has a pointedprojection 0', Fig. 10, which contacts with a pointed apex P of asliding block P in a suitable guide way in rear of pawl O, the blockbeing held in a forward position by a spring U in rear thereof. By meansof handle T the tension of the spring U may be overcome, throwingprojection O of the double pawl to either one or the other side of thesliding block, thereby engaging either of the pawls as may be requiredto turn ratchet wheel F to the right or left and thus raise or lower thelifting bar.

Q is an apertured cover of suitable shape to fit in the large end of thelever to protect the ratchet mechanism and to hold the same in place.This cover may be fastened in place by a rivet passing through apertureR in the plate, and the rivet also passing through and serving as apivot for the double ratchet O to turn upon.

K is removable cap of suitable form to fit on the upper end of thelifting bar, when required to raise and support the load.

The operation of the jack is as follows: The gearingis put intooperative position, as shown in Figs. 1 and 3, and the jack placed underthe load which is desired to be raised. By means of handle T, theprojection O is thrown to the right or below apex P of the sliding blockwhich throws the right hand or lower pawl of the double pawl intocontact with the ratchet wheel and by raising and lowering lever F theconnecting gearing will raise the lifting bar and the load restingthereon. If it is desired to lower the load slowly, the right hand pawlmay be thrown out and the left hand pawl thrown into contact with theratchet wheel, and by operating the lever lifting bar and load restingthereon will be lowered. If it' is desired to lower the jack quickly,all that is necessary is to throw the bottom of dog J outward; this willpermit the worm E to drop downward out of gear with worm wheel D, andthejack will quickly run down of its own accord.

It is evident that many changes may be made in the construction andarrangement of parts withoutdeparting from the spirit of the invention.

What we claim, and desire by Letters Pat cut, is

1. In a jack, the combination of a lifting bar having a rack, apinionmeshing with the rack and a worm wheel mounted on the same shaft as thepinion, a second shaft a frame in I which the latter shaftisjournaled,aworm on the latter shaft engaging theworm wheel, said framepivoted at oneend in an outer shell, and a dog pivoted in the outershell underneath the frame and adapted to support said frame and holdthe worm in mesh with the worm wheel, a ratchet lever with an enlargedapertured end to fit the squared end of the second shaft, a ratchetwheel, and a spring-actuated double pawl to revolve the second shaft andoperate the jack, substantially as described and set forth.

2. The combination in a jack of a lifting bar having a rack, a pinionengaging the rack, and a worm wheel mounted on the same shaft as thepinion, a worm, a frame with a closed bottom, the frame being pivoted atone end in the outer shell, a dog pivoted in the outer shell underneaththe frame, the upper end of the dog supporting the opposite end of saidframe to hold the worm in mesh with the worm-wheel, and a lever with anenlarged apertured end to engage the squared end of the second shaft tooperate the jack, as and for the purposes set forth.

In testimony whereof we afiix our signatures in presence of twowitnesses.

JOHN A. MEAD. CHARLES JOHNSON. Witnesses:

CARL B. HINSMAN, RUST P. BARRETT.

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